2.3 The following unbalanced reaction produces 120 g of \( \mathrm{PF}_{3} \) and has a \( 78.1 \% \) yield. \[ P_{4}(s)+F_{2}(g) \rightarrow P F_{3}(g) \] 2.3.1 Write a balanced equation for this reaction. 2.3.2 Calculate the theoretical yield of \( \mathrm{PF}_{3} \) (1) 2.3.3 Calculate the mass of \( \mathrm{F}_{2} \) needed for this reaction.

Please select the molecule(s) with resonance structures from the following. CCl 4 CHCl 3 SO 3 H 2 O None

Which of the following represent a buffer system? Check all that apply. \( \square \mathrm{NaOH} \) and NaCl \( \square \mathrm{H}_{2} \mathrm{CO}_{3} \) and \( \mathrm{NaHCO}_{3} \) HF and KF KCl and NaCl

The pH scale for acidity is defined by \[ \mathrm{pH}=-\log \left[\mathrm{H}^{+}\right] \] where \( \left[\mathrm{H}^{+}\right] \)is the concentration of hydrogen ions measured in moles per liter (M). a) A sample of rhubarb is found to have a hydrogen concentration of 0.000501 M . What is the pH? Round your answer to 2 decimal places. \( \mathrm{pH}=\square \) b) The pH of a sample of red onion is 5.40 . What is the hydrogen concentration? Keep at leost 2 non-zero decimal ploces. \( \left[\mathrm{H}^{*}\right]=\square \)

Which of the following molecule(s) have lone pair electrons and/or non-identical central bonds? \( \mathrm{CCl}_{4} \) \( \mathrm{CHCl}_{3} \) \( \mathrm{SO}_{3} \) \( \mathrm{CO}_{2} \mathrm{O} \)

Please select polar molecule(s) from the following. \( \square \mathrm{CCl} 4 \) \( \square \mathrm{CHCl} 3 \) \( \square \mathrm{CO} 3 \) CO 2